import threading as td
import time

def change(n):
    global mun
    for i in range(10000000):
        mun += n
        mun -= n


def star():
    t1 = td.Thread(target=change,args=(5,))
    t2 = td.Thread(target=change,args=(8,))
    t1.start()
    t2.start()
    t1.join()
    t2.join()

if __name__ == '__main__':
    mun = 0
    time1 = time.time()
    star()
    time2 = time.time()
    print(time2 - time1)
